1. Field of the Invention
The present invention relates to a magnetic random access memory (MRAM) of a spin injection magnetization reverse type, and a manufacturing method of the memory.
2. Description of the Related Art
In recent years, a magnetic random access memory (MRAM) of a spin injection magnetization reverse type has been expected as a low-current MRAM technology of the next generation.
In the spin injection magnetization reverse type, for example, a structure of a 1Tr+1MTJ type is employed. In this structure of the 1Tr+1MTJ type, an interconnect is connected to one end of a magnetic tunnel junction (MTJ) element via a contact, and a transistor is connected to the other end of the MTJ element. Here, the contact largely comes into contact with the MTJ element. This is because the MTJ element having a small area is assumed to reduce the current of spin injection writing.
However, to reverse magnetization of the MTJ element, spin electrons required for reversing the whole magnetization of the MTJ element need to be injected thereinto from a contact which is larger than the MTJ element. Therefore, lowering of the current of the memory can be realized. However, an amount of the current flowing through one MTJ element and one transistor increases, and this fact has been inconvenient from a viewpoint of cell design.
It is to be noted that prior art document information concerned with the invention of this application is as follows:    [Patent Document 1] Jpn. Pat. Appln. KOKAI Publication No. 2005-340300;    [Patent Document 2] Jpn. Pat. Appln. KOKAI Publication No. 2004-146821; and    [Patent Document 3] Jpn. Pat. Appln. KOKAI Publication No. 2006-120742.